New septic system installation around Fort Smith

Building on a rural lot in Sebastian or Crawford County, or replacing a system that has finally quit, means a new septic system, and in Arkansas that runs through the Arkansas Department of Health (ADH). The rules are the state's Rules Pertaining to Onsite Wastewater Systems (effective September 5, 2024). Here is how a new system gets from bare ground to a permit for operation, and why River Valley soil decides so much of the price.

First question: is sewer close enough?

Under ADH rule 4.1, a property has to connect to a sanitary sewer when one is within 300 feet of where the sewer line leaves the house and the connection doesn't cross someone else's land. On the edges of Fort Smith, Van Buren, Alma and Greenwood that can settle the question before anyone digs a soil pit.

The steps, in order

1. A Designated Representative evaluates the site. A Designated Representative (DR) is someone ADH certifies to do percolation tests, system designs and inspections: engineers, land surveyors, master plumbers, sanitarians and similar (rule 2.9). The DR digs at least two soil pits, one where the main field would go and one for the backup (secondary) area, and records the depth to the seasonal water table, any bedrock, and each soil layer (rule 7.1).
2. The perc test, if it's used. Test holes are soaked, preferably overnight and never less than four hours, so clay can swell the way it does in a wet spring, then the water drop is timed. Soil that percs slower than 75 minutes per inch is unsuitable for a standard system (rule 8.5.2). Tight River Valley clay is exactly where that line gets tested.
3. The permit for construction. The DR fills out Part I of the permit application (form EHP-19) with the soil results, lot dimensions and the design, and the county health unit approves it before any work starts (rule 4.10.1). The ADH plan review fee goes by the house's square footage: $30 up to 1,500 sq ft, then $45, $90, $120, and $150 over 4,000 sq ft; repairs and alterations are $30. A construction permit is good for one year.
4. A registered installer builds it. Installers must be registered with ADH, pass an exam, take a training course each year, and be on site for every phase of construction. They have to notify the health unit 24 hours before starting (rules 14.1 and 14.3).
5. Inspection, then a permit for operation. The installation is inspected, and the system can't be used until the permit for operation is issued (rule 4.10.3). Keep your copy; it is the record a future buyer, pumper or inspector will ask for.

How big a tank

ADH sizes residential tanks by bedrooms, not by how many people live there today: a minimum of 1,000 gallons for up to three bedrooms, plus 250 gallons for each bedroom beyond that (Appendix C). The design flow for a three-bedroom house is 370 gallons a day (Appendix B). Once yours is in, the septic pumping calculator shows roughly how often a tank that size will need pumping.

Where it can go

The state's minimum distances (rule 6.2) shape a lot of rural layouts here:

• 100 feet from any well or other domestic water supply
• 100 feet from the high-water mark of a stream or lake, and from any sinkhole
• 50 feet from a pond on your own property (100 feet from a neighbor's pond in the same watershed)
• 10 feet from the house or any building, from property lines, and from the water service line

Those are minimums; the health unit can require more where local conditions call for it.

Conventional or alternative?

A standard system is a septic tank feeding absorption trenches sized from the soil data. When the soil won't take it (heavy clay, shallow shale or sandstone, a high seasonal water table near the Arkansas River and the creek bottoms), the design moves to an alternative: low-pressure distribution, a sand filter, drip dispersal, or an aerobic treatment unit. ATUs must be authorized by ADH and listed under NSF/ANSI Standard 40, with a visual and audible alarm (rule 11.3 and Appendix D). Owners of alternative systems must keep a monitoring contract with an ADH-registered monitoring person for the life of the system, with an assessment at least every six months, and homeowners can't monitor their own (Section 12).

What drives the cost

• The soil result. Whether the site passes for a standard field or needs an alternative system is the biggest single swing in price.
• Bedrooms. They set the tank size and the size of the field.
• Rock and slope. Shallow rock slows excavation, and a field uphill from the house needs a pump tank and controls.
• Ongoing costs. Alternative systems carry the monitoring contract and power for pumps or aerators.
• Replacing an old system. If you're here because a field failed, see drain field problems first; sometimes the old field can be saved.

The installer quotes the job after the soil work is done; we don't set prices.